Preliminary Diagnosis: Gastrinoma

I. What imaging technique is first-line for this diagnosis

II. Describe the advantages and disadvantages of this technique for gastrinoma.

Advantages

Has good spatial resolution and allows for localization and enhancement characterization of pancreatic endocrine tumors

Has high sensitivity but may require complementary imaging

Can identify hepatic and other metastatic lesions

Can identify non-hyperfunctioning pancreatic endocrine tumors

Disadvantages

Ionizing radiation

May require additional complementary imaging

III. What are the contraindications for the first-line imaging technique?

Known allergy to intravenous contrast

Decreased renal function

Pregnancy

IV. What alternative imaging techniques are available?

MR with and without contrast

Angiography

Nuclear imaging: options and availability will vary by institution

V. Describe the advantages and disadvantages of the alternative techniques for gastrinoma.

MR with and without contrast

Advantages

Lack of ionizing radiation

Has comparable sensitivity and ability to identify metastases as CT

Disadvantages

Requires a longer scan time

Requires a higher level of patient compliance and can be more prone to artifact

Angiography

Advantages

Hepatic vein sampling and pancreatic arterial stimulation allows for evaluation of functional status and can be diagnostic.

Disadvantages

Ionizing radiation

Limited to patients who can tolerate intravenous contrast

Nuclear imaging

Advantages

Several options exist including octreotide-based radionuclides, PET/CT, as well as newer agents targeted against a wider range of somatostatin receptors.

Clinical utility may vary depending on the type of endocrine neoplasm. For instance, gastrinomas may have a greater imaging sensitivity than insulinoma due to relatively higher expression of somatostatin receptors.

Disadvantages

Ionizing radiation

Nuclear imaging options and availability will vary by institution. Consultation is recommended to optimize the study.

VI. What are the contraindications for the alternative imaging techniques?